The strong growth in the number of Internet users and services provided through the Internet has been one of the most remarkable phenomena in communications in recent years. Another current trend is the strongly increasing use of various mobile terminals, such as laptops, PDA (Personal Digital Assistant) equipment, and intelligent telephones.
These two rapidly evolving network technologies, wireless communication and the Internet, are gradually converging to make the packet switched data services used in the Internet available to mobile users. So far this converging development has been taking place rather slowly, since most of the technology developed for the Internet has been designed for desktop computers and medium or high bandwidth data connections. It has, therefore, been difficult to introduce the IP-based (IP=Internet Protocol) packet services to the mobile environment, which is characterized by less bandwidth and poorer connection stability in comparison to fixed networks, and where the terminals have many fundamental limitations, such as smaller displays, less memory, and less powerful CPUs, as compared to fixed terminals. However, the development of IP-based packet services for the mobile environment will occur at an increasing rate in the foreseeable future. This is partly due to the demand created by the market and partly due to the evolvement of new technologies designed to meet the various requirements of mobile networks, such as sufficient quality of service and data security. The increasing market demand is based on the rapid increase in the popularity of the Internet: Internet users are often also mobile subscribers and thus may also want to use their mobile terminals for services familiar to them from the Internet environment. This commercial demand in turn enables investments necessary for the development of mobile services. The said new technologies include GPRS (General Packet Radio Service), UMTS (Universal Mobile Telecommunication System), and WAP (Wireless Application Protocol), for example. GPRS aims at providing high-quality services for GSM subscribers by efficiently utilizing the GSM infrastructure and protocols. WAP, in tum, defines a set of standard components enabling communication between mobile terminals and servers providing service in the network. WAP utilizes proxies which connect the wireless domain with the WWW domain.
The introduction of services in these new network environments is not a straightforward task, due to the different network technologies used and the fact that several parties (organizations) are involved. One area to be solved in connection with the introduction of services is the implementation of billing, i.e. how to implement efficient billing processes when an end user who is typically in the wireless domain uses the services provided by the WWW domain. In a typical service architecture the clients access the services through a gateway and a separate entity is provided for managing the actual billing. This entity is in this context called the ISB (Internet Service Broker). The ISB keeps the accounts of the subscribers and performs various functions associated with billing. The ISB also serves as an entity through which the subscribers can subscribe to the services provided by the content servers in the network.
European published Patent Application 924630 describes a service architecture of the above-described kind where a separate proxy server handles access control. In order to find out the price related to a resource requested by a client, the proxy intercepts all resource requests directed to a content server. The proxy caches each request and sends a header request to the content server, requesting the content server to transmit a header associated with the requested resource back to the proxy. The header informs the proxy about the billing and/or access information associated with the requested resource, whereby the proxy authenticates the client's right to receive the requested resource whenever the header indicates that there are billing and/or access restrictions involved. The authentication is performed with an ISB taking care of client identification, authentication, and billing.
When offering the services, the Service Provider (which refers to the party providing the services from the content servers) and the ISB face a credit loss risk if the credit standing of the subscriber has not been successfully verified or the service has not been paid for beforehand. In the case of some subscribers this risk may be acceptable; for them the ISB, the Service Provider or an external party, such as a credit card company, takes the responsibility for such a risk.
However, from the point of view of the ISB and/or the Service Provider, it would be desirable to be able to verify the liquidity of all those subscribers to which to a credit loss risk is associated. These subscribers are typically prepaying customers, whereby the verification would involve checking that the current balance of the subscriber account is sufficient for the service in question. On the other hand, for performance reasons it is most often not possible to check the account balance of such subscribers at the beginning of each transaction to ensure that the subscriber is capable of paying the service requested by him/her. This applies especially to large ISB systems serving a number of gateways through which the services are accessed.
The objective of the invention is to obtain a solution for the above problem in a service environment where an acknowledgment of a successful delivery of the service is available for most services. This acknowledgment can be available, for example, from the application level implementation, from the service transport protocol layer, or from a logistical information base.